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| Allan Hills 12073 | |||||||||||||||||||||||||||
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| Basic information | Name: Allan Hills 12073 This is an OFFICIAL meteorite name. Abbreviation: ALH 12073 Observed fall: No Year found: 2012 Country: Antarctica [Collected jointly by Programma Nazionale di Ricerche in Antartide (PNRA), Italy, and Korean Expedition for Antarctic Meteorites (KOREAMET)] Mass:  0.5 g | ||||||||||||||||||||||||||
| Classification history: |
This is 1 of 576 approved meteorites (plus 1 unapproved name) classified as Eucrite. [show all] Search for other: Achondrites, Eucrites, and HED achondrites | ||||||||||||||||||||||||||
| Comments: | Approved 15 May 2016 | ||||||||||||||||||||||||||
| Writeup |
Writeup from MB 105:
Allan Hills 12073 (ALH 12073) 76°42.750’S, 158°46.926’E Antarctica Find: 2012 Dec 24 Classification: HED achondrite (Eucrite) History: A small, meteorite with minor weathering was found in the Allan Hills near the Western Icefield during the XXVIII PNRA Italian expedition, 2012-2013 (in collaboration with KOREAMET) Physical characteristics: Small, uncrusted stony fragment (6 × 5 × 5 mm) Petrography: (J. Nava, M. Gemelli, M. D’Orazio, T. Di Rocco, L. Folco, DST-PI) holocrystalline rock with subophitic igneous texture. Inequigranular rock with medium to fine-grained crystals. Meteorite dominated by plagioclase (47 vol%) and low-Ca pyroxene (35 vol%), with minor tridymite (7 vol%; identified by Raman spectroscopy), high-Ca pyroxene (4 vol%), sulfides (4 vol%), phosphates (2 vol%), Fe,Ni metal (1 vol%), and spinel (tr.). Poikilitic plagioclase grains, up to 1 mm across, enclose anhedral low-Ca pyroxene and tridymite (<100 μm). Subhedral grains of low-Ca pyroxene (up to 1 mm) often contain inclusions of rounded plagioclase (<100 μm) and exsolution lamellae of high-Ca pyroxene, which also occurs as small isolated interstitial grains (up to 100 μm). Tridymite occurs as large lath-shaped crystals (0.5-1 mm). Geochemistry: (J. Nava and M. Gemelli, EMP at CNR Padua) Plagioclase, An92.4±1.7Ab7.5±1.6Or0.2±0.1; low-Ca pyroxene, En63.1±0.8Fs 33.9±0.7Wo3.1±0.5, Fe/Mn=25±2 (n=52); high-Ca pyroxene, En43.3±1.1Fs16.1±1.1Wo40.5±1.7, Fe/Mn=23±3 (n=22); troilite, Fe=63.2, S=36.6 (wt%). Oxygen Isotopes: (A. Pack, UGött): δ18O = 4.4 ‰, δ17O = 2.04 ‰, Δ17O = -0.266 ‰. Classification: Eucrite Specimens: Main mass (0.1 g), type specimen and one thin section (MNA-SI). | ||||||||||||||||||||||||||
| Data from: MB105 Table 0 Line 0: |
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| Plots: | O isotopes: | ||||||||||||||||||||||||||
| Institutions and collections |
DST-PI: Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, 56126 Pisa, Italy (institutional address; updated 17 Oct 2011) MNA-SI: Museo Nazionale dell'Antartide, Università di Siena, Via Laterina 8, I-53100 Siena, Italy; Website (institutional address; updated 13 Dec 2011) CNR: Instituto di Geoscienze e Georisorse, Consiglio Nazionale delle Richerche, Sez. Di Padova, Corso Garibaldi 37, 35100 Padova, Italy (institutional address) |
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| References: | Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
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Geography:
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Statistics: This is 1 of 43856 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||||
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